How does inheritance work in Object-Oriented COBOL, and what benefits does it offer?
- By defining the size and type of data
- By optimizing program execution
- By organizing data in memory
- Inheritance allows a class (subclass) to inherit attributes and behaviors from another class (superclass). Benefits include code reuse, extensibility, and the ability to model relationships between classes.
In Object-Oriented COBOL, inheritance enables a subclass to inherit properties from a superclass, promoting code reuse, extensibility, and the modeling of relationships. A subclass can reuse attributes and behaviors from its superclass, leading to more maintainable code.
You are working on a COBOL program that processes a customer database with the potential for duplicate customer IDs. How would you efficiently identify and handle duplicate customer records to ensure data accuracy?
- Implement a hash function to identify duplicate customer IDs
- Use a SORT and MERGE process to eliminate duplicates based on customer IDs
- Use a sequential search to identify and remove duplicate customer records
- Utilize a COBOL table to store unique customer IDs and compare incoming records
Using a SORT and MERGE process is an efficient way to eliminate duplicate customer records based on customer IDs, ensuring data accuracy in the customer database. It involves sorting the data based on customer IDs and merging the records to eliminate duplicates.
The _____ clause is used to specify the file organization for a COBOL file.
- DATA DIVISION
- ENVIRONMENT DIVISION
- FILE-CONTROL
- RECORDING MODE
In COBOL, the FILE-CONTROL clause is used to specify the organization of files. It includes clauses like SELECT and ASSIGN, allowing you to define the file structure and its associated external resources.
When using the REDEFINES clause, it's essential to ensure that the redefined data items have the same starting _____
- Data Types
- Lengths
- Names
- Values
Ensuring that redefined data items have the same starting lengths is crucial when using the REDEFINES clause in COBOL. It helps in preventing data misalignment and memory allocation issues.
The EXIT statement can include a numeric operand that specifies the ___________ code to return to the operating system.
- Completion
- Error
- Exit
- Return
The EXIT statement in COBOL can include a numeric operand that specifies the exit code to return to the operating system. This allows the program to communicate its completion status to the calling environment.
To improve performance, COBOL programs often use file ____________ to temporarily store records during processing.
- Archiving
- Buffering
- Indexing
- Sorting
Buffering is a technique used in COBOL to enhance performance by temporarily storing records in memory during processing. It reduces the need for frequent disk access, thereby optimizing I/O operations.
When performing database operations, the _____ statement is used to commit changes to the database.
- COMMIT WORK
- EXEC SQL COMMIT
- EXEC SQL ROLLBACK
- ROLLBACK WORK
When performing database operations, the COMMIT WORK statement is used in COBOL to commit changes made during the transaction to the database. It ensures the changes are permanently saved.
The ________ clause in COBOL is used to specify the number of times a group data item can occur.
- DEPENDING ON
- INDEXED BY
- OCCURS
- REDEFINES
The OCCURS clause in COBOL is used to specify the number of times a group data item or an elementary data item can occur in a table or an array. It defines the occurrence of a particular data item or group.
Which COBOL data type allows you to store both numeric and alphabetic characters?
- PIC 9
- PIC A
- PIC X
- PIC X(10)
The COBOL data type PIC X(10) allows you to store both numeric and alphabetic characters in the same field. It is a flexible alphanumeric field that can accommodate a mix of characters.
When working with indexed files, which access mode is commonly used to update existing records?
- "Dynamic" access mode
- "Extend" access mode
- "Random" access mode
- "Sequential" access mode
The "Random" access mode in COBOL is commonly used when working with indexed files to update existing records. It allows direct access to any record in the file based on the key value.
How does COBOL handle multi-dimensional arrays?
- By defining separate one-dimensional arrays
- By using nested OCCURS clauses
- By using the MULTI-DIMENSIONAL keyword
- COBOL does not support multi-dimensional arrays
COBOL handles multi-dimensional arrays by using nested OCCURS clauses. This allows the creation of tables with multiple levels, providing a structured way to represent data in multiple dimensions.
How is the OCCURS clause used to define an array in COBOL?
- By indicating the start and end indices
- By setting the REDEFINES attribute
- By specifying the number of occurrences and the data type
- By using the INDEXED BY phrase
To define an array in COBOL using the OCCURS clause, you specify the number of occurrences and the data type of the array elements. This allows the compiler to allocate memory for the array and enables efficient indexing and manipulation of array elements.